What rated battery cable do I need?

[Rick-sta]

I'm going to be fitting a battery isolator cut off switch to my diesel ZT which will save me having to remove the strut brace every time I disconnect the battery when it's in the garage unused for a while.

I need to order some battery cable in order to fit the switch, what rated cable will I need? what amp rating?

Cheers
Rick

[T-Cut]

I suspect my guess is as good as yours. For a 2 litre diesel I'll say 200amps. Can you not measure the cross sectional area of the existing cable and use that to define what you need? It's sold by cross section as well as amp rating.


TC

[RoverP480]

AES quote both Dia, cross section and current capability
https://www.autoelectricsupplies.co....2/category/124

[Arctic]

pick your own Terminal hole diameter.

https://www.ebay.co.uk/itm/170-Amp-C...r=521515635838

https://www.ebay.co.uk/itm/240-Amp-C...wAAOSwqiRdiKyZ

When I added an extra earth to my FL2 I used a strap from an MGZT albeit a positive strap but I added some conduit.

[DMGRS]

I believe the starters are rated at 2.2Kw - so I'd go for 3Kw to be safe.
Assuming 12v, that's 250 amps - you'll need some pretty meaty cable!

I was shocked how thick the battery to boot cables are on my 530d and the ZT260. If in doubt, grab a battery to boot cable from a BMW at the scrapyard (a diesel to make sure it's thick enough).

[COLVERT]

Originally Posted by Rick-sta

I'm going to be fitting a battery isolator cut off switch to my diesel ZT which will save me having to remove the strut brace every time I disconnect the battery when it's in the garage unused for a while.

I need to order some battery cable in order to fit the switch, what rated cable will I need? what amp rating?

Cheers
Rick

Have you bought the switch ??

There are isolating switches that connect straight to the battery and the existing cable is then fitted into the end.

[RoverP480]

Originally Posted by DMGRS

I was shocked how thick the battery to boot cables are on my 530d and the ZT260. If in doubt, grab a battery to boot cable from a BMW at the scrapyard (a diesel to make sure it's thick enough).

You can get away with smaller cross section with short runs but to keep the voltage drop manageable on long ones you need to up the size.

[COLVERT]

Originally Posted by RoverP480

You can get away with smaller cross section with short runs but to keep the voltage drop manageable on long ones you need to up the size.

It's the AMPERAGE drop you have to worry about.---

[COLVERT]

Originally Posted by Rick-sta

I'm going to be fitting a battery isolator cut off switch to my diesel ZT which will save me having to remove the strut brace every time I disconnect the battery when it's in the garage unused for a while.

I need to order some battery cable in order to fit the switch, what rated cable will I need? what amp rating?

Cheers
Rick

Hi there, Rick.

Auto Electrical Wiring Products for Modern, Classic & Vintage Vehicles

This company does switches for £8.00 that fit straight onto the battery terminal. Your existing wire goes straight into the switch. No need to mess about with extra cable and the attendant problems of sizing and cutting it.
This unit can be fitted ,easily, in less than 5 minutes.




Colvert.---

[Rick-sta]

Originally Posted by COLVERT

Hi there, Rick.

Auto Electrical Wiring Products for Modern, Classic & Vintage Vehicles

This company does switches for £8.00 that fit straight onto the battery terminal. Your existing wire goes straight into the switch. No need to mess about with extra cable and the attendant problems of sizing and cutting it.
This unit can be fitted ,easily, in less than 5 minutes.




Colvert.---

Thanks Jon already seen those but no good for as in my OP the reason for fitting the switch outside of the battery box is because I have a strut brace fitted which has to be removed in order to get the battery box lid off to access the battery. Fitting a switch outside of the battery box saves all that hassle